Activity Regulation by Heteromerization of Arabidopsis Allene Oxide Cyclase Family Members

0471365 - ÚEB 2017 RIV CH eng J - Journal Article
Otto, M. - Naumann, Ch. - Brandt, W. - Wasternack, Claus - Hause, B.
Activity Regulation by Heteromerization of Arabidopsis Allene Oxide Cyclase Family Members.
Plants. Roč. 5, č. 1 (2016), č. článku 3. E-ISSN 2223-7747
R&D Projects: GA MŠMT(CZ) LO1204
Institutional support: RVO:61389030
Keywords : Activity regulation * Arabidopsis allene oxide cyclase isoforms * Heteromerization
Subject RIV: EB - Genetics ; Molecular Biology

Jasmonates (JAs) are lipid-derived signals in plant stress responses and development. A crucial step in JA biosynthesis is catalyzed by allene oxide cyclase (AOC). Four genes encoding functional AOCs (AOC1, AOC2, AOC3 and AOC4) have been characterized for Arabidopsis thaliana in terms of organ- and tissue-specific expression, mutant phenotypes, promoter activities and initial in vivo protein interaction studies suggesting functional redundancy and diversification, including first hints at enzyme activity control by protein-protein interaction. Here, these analyses were extended by detailed analysis of recombinant proteins produced in Escherichia coli. Treatment of purified AOC2 with SDS at different temperatures, chemical cross-linking experiments and protein structure analysis by molecular modelling approaches were performed. Several salt bridges between monomers and a hydrophobic core within the AOC2 trimer were identified and functionally proven by site-directed mutagenesis. The data obtained showed that AOC2 acts as a trimer. Finally, AOC activity was determined in heteromers formed by pairwise combinations of the four AOC isoforms. The highest activities were found for heteromers containing AOC4 + AOC1 and AOC4 + AOC2, respectively. All data are in line with an enzyme activity control of all four AOCs by heteromerization, thereby supporting a putative fine-tuning in JA formation by various regulatory principles.
Permanent Link: http://hdl.handle.net/11104/0268957